What Gears should I run?

[1993gmc]

I have a 2000 K2500 4x4 with the 454 in it. I have 38.5/14.5x16.5 tires on it with just stock hwy gears in it. I believe they are 3.73?? What gears would be best for me to use. I only drive the truck on the road, mostly crusing around 80-100KM/H. The truck is very gutless with the big tires and I haven't got 300KM to a tank of fuel yet. Any sugestion would be great, I don't know very much about gearing.

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[SwampHound]

5.13s or 5.38s would be your best bet for that size tire. Would definitely get back your power and some mileage

 

[SCOTTYINWV]

I definitely wouldn't go under a 4.88, but Imo a 5.13 or lower would be better suited. Check your rpo codes in the glove box. It's on a white label with a bunch of 3 digit codes. Should be something like a gu6, gt4, gt5. Your mileage is way the heck oFF woth that large of a tire, stock gearing and an uncalibrated speedometer/odometer.

 

[cjman250]

I would go 4.88 or 5.13

 

[98sierra4x4]

I have a 2000 K2500 4x4 with the 454 in it. I have 38.5/14.5x16.5 tires on it with just stock hwy gears in it. I believe they are 3.73?? What gears would be best for me to use. I only drive the truck on the road, mostly crusing around 80-100KM/H. The truck is very gutless with the big tires and I haven't got 300KM to a tank of fuel yet. Any sugestion would be great, I don't know very much about gearing.

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Nice truck, got a build thread?


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[98_k1500]

My vote is for 4.88 if its manual, 5.13 if its auto. Not really a lot of difference in the 2, but that would be my choice.

+1 on a build thread.

 

[highperf4x4]

If you plan to stay with the 38.5" then I would recommend the 4.88 also. I run 4.56 with 35" and it's pretty low. I come off the line hard with a 383. I only get 46 mph wheel speed out of first gear with a th400 which has about the highest first gear of the autos. If you're running the manual I would go with 4.56.